The objectives of the proposed research are two-fold: 1) to understand the detailed cellular organization of central pattern generators, that is, neuronal circuits within the central nervous system that generate patterned motor behavior such as posture and locomotion; 2) to study the roles of biogenic amines in the organization or modulation of motor output. The eventual goal of the work is to understand at the single-cell level the biochemical events that underlie motor co-ordination and functional plasticity in motor output. This will provide a valuable basis for studying diseases of motor dysfunction that appear to have a neurogenic cause. The major study will be on the central pattern generators for abdominal posture in the lobster, Homarus americanus. In this simple, model system, single neurons involved in directing posture can be morphologically and neurophysiologically detected. Octopamine and serotonin induce stereotyped abdominal postures in the lobster. Biochemical and morphological analyses will be used to detect the presence and release of these amines in the central nervous system. Neurophysiological and pharmacological experiments will be done to deduce the role and cellular targets of the amines in the postural pattern generator circuits. Elucidation of the roles of amines in the circuits will give us a better understanding of the ways in which circuits of neurons interact to create patterned motor output and modulate that output. To extend this single-cell approach to vertebrates, a second study will be begun on the spinal cord pattern generator circuits for swimming in the sea lamprey, Petromyzon marinus. Cells involved in generating the undulating swimming rhythm will be physiologically identified and the effects of amines on cellular membrane properties as well as the swimming rhythm will be determined. This study will begin a biochemical analysis of neurotransmitters involved in motor co-ordination in vertebrates, and will provide information which can then be tested in more complex vertebrates that are too difficult to study by today's technology.